Technical Cautions - Hitachi 36UX59B Service Manual

1 MSLXU
TECHNICAL CAUTIONS
High Voltage Limiter Circuit Operation Check and Overvoltage Protection Circuit Operation Check
Adiustment Preparation
1. Connect a High Voltage Voltmeter between CPT Anode terminal (Anode capside) and Ground.
2. Set the AC input voltage to 120r3V.
3. Receive Circle Pattern or Broadcast Signal and set "BRIGHTNESS" and "CONTRAST" to maximum. Adjust the
SCREEN VR so that Beam Current is
le+O.l
mA. (The voltage at ABL terminal (C747) should be 12V or less.)
1
CPT Anode
High Voltage Voltmeter
(DC Voltage Divider)
Use the voltmeter which can
indicate up to the first decimal
point with an impedance of
Gl
lOMS2 or more.
+
+
*
1
-0 -
c----
-
DIgital Voltmeter
CPT Ground Wire
Adiustment Procedure
1. Check that the normal High Voltage and +B Voltage as below.
I
CHASSIS 1 EHT+l kV 1 IB+-O.lmA 1 +B
I
cz97,cz95, cz93 30.0kV
1.7mA 140+0.3v
CY97,CY95, CY93
29.OkV
1.5mA 140f0.3V
Less than 12V
CPT Anode
CPT Ground Wire
(TP701)
Voltage Voltmeter
(DC Voltage Divider)
I
I
Use the voltmeter impedance 1OMQ or mora with indication to the first decimal place.
2. Connect a 10KQ 1/8W resistor to both ends of D708 and check that power is turned off.
R736
D708
3. Disconnect the AC plug and remove the 10kB resistor.
9